French authorities are investigating whether Apple deliberately slows down older iPhones in order to increase sales, AFP reports.

The move follows a complaint by a French consumer group, HOP, that campaigns against planned obsolescence and which filed a complaint against Apple in December.

Programmed obsolescence is illegal in France under a 2015 law which prohibits “the use of techniques by which the person responsible for the marketing of a product aims to deliberately reduce the duration to increase the replacement rate “.

The law carries a penalty of a maximum sentence of two years in prison and up to 5 per cent of a company’s annual turnover.

AFP cites a judicial source stating that the Paris prosecutor’s office of the Directorate General of Competition, Consumption and Repression of Frauds opened a preliminary investigation against Apple on January 5, for “programmed obsolescence” and “deception”.

We’ve contacted Apple for comment and will update this story with any response.

In December Apple responded publicly to complaints that it throttles performance on older iPhones, saying it was managing performance in order to prolong the life of devices by avoiding unexpected shutdowns caused by older batteries not being able to handle peaks of processing power.

It subsequently apologized for not being more transparent about how it handles performance on iPhones with older batteries — writing in a message to customers that “we have never — and would never — do anything to intentionally shorten the life of any Apple product, or degrade the user experience to drive customer upgrades”, and saying its goal is to make “iPhones last as long as possible”.

It also began offering a battery replacement for affected older devices for a reduced $29.

In a statement, Laetitia Vasseur, HOP co-founder and general delegate, said: “Everything is orchestrated to force consumers to renew their smartphones. However, at more than €1,200 the phone, more than a SMIC [minimum monthly wage], these practices are unacceptable and can not go unpunished. It is our mission to defend consumers and the environment against this waste organized by Apple.”

In its campaigning against programmed obsolescence, the HOP group also calls generally for greater transparency from companies and for software updates to be reversible, as well as urging smartphone makers to offer devices with removable batteries.